curl_close is a no-op since PHP 8.0, so drop it

Author: nickygerritsen

judge/judgedaemon.main.php

@@ -686,7 +686,6 @@ private function setupCurlHandle(string $restuser, string $restpass): \CurlHandl
     private function closeCurlHandles(): void
     {
         if (!empty($this->endpoint['ch'])) {
-            curl_close($this->endpoint['ch']);
             unset($this->endpoint['ch']);
         }
     }